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KZ AR15/M4 Receiver Extension Buffer Tube Block

(13 reviews) Write a Review
1.00 LBS
  • Designed to aid in the assembly of lower receivers. Once the armorer has installed the buffer tube onto the lower; the buffer tube and lower receiver assembly can be slid into the duo rings at the 12, 3, 6 and 9 o’clock positions.

This allows the armorer to rotate the lower in 90 degree increments in the block simply by loosening the provided nylon screws, removing the lower, and sliding it back in at the desired orientation. 

The Reaction Block provides an ultra-stable platform for performing an array of lower receiver operations, as well as making the installation of the buffer retainer nut quick and easy. All while keeping both hands of the armorer free to work, saving both time and frustration.
  • KZ AR15/M4 Receiver Extension Buffer Tube Block
  • KZ AR15/M4 Receiver Extension Buffer Tube Block
  • KZ AR15/M4 Receiver Extension Buffer Tube Block
  • KZ AR15/M4 Receiver Extension Buffer Tube Block
  • KZ AR15/M4 Receiver Extension Buffer Tube Block
  • KZ AR15/M4 Receiver Extension Buffer Tube Block

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Frequently bought together:


The Kley-Zion Buffer Tube Buddy was designed for assembly and maintenance of the AR15/M4 lower receivers.


  • Will work with both mil-spec & commercial buffer tubes
  • Mounts receiver in 12, 3 , 6 or 9 o'clock positions
  • Two polymer screws firmly holds buffer tube in position.
  • Mounts in any vice
  • 6061 T6 Aluminum
  • Clear, Type II class III hard Anodized
  • Only, 3.5" wide, 6" tall
  • Lightweight only 11.6oz
  • Lifetime warranty
  • 100% Made In USA

WARNING This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

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Additional Information

Product ID:
Armorer's Tools
Made In USA
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13 Reviews

  • 5
    KZ Receiver extension tool

    Posted by Bryan L on 30th Nov 2020

    Price, Quality, ease of use deserve 5 stars....no complaints! I’ve built 16 lowers so far and it does what its supposed to!

  • 5
    buffer tube block

    Posted by Willam on 20th Oct 2020

    Exactly what I needed, exceeded my expectations.

  • 5
    Buffer tube block

    Posted by Kenneth Lambert on 29th Jul 2020

    Fantastic product!!!!!!! If you don't have one buy this one you want be disappointed.

  • 5
    Buffer tube block

    Posted by Kenneth Lambert on 14th Jul 2020

    Fantastic tool easy to use and does the job without damage to the receiver.

  • 5
    KZ AR15 Receiver Extention Buffer Tube Block

    Posted by Wolfgar on 23rd Mar 2020

    I was able to easily torque my AR receiver buffer tube to the specified 40ft pounds without twisting the receiver plate and stripping the buffer tube threads. Worked just as it was advertised. I would highly recommend this without any hesitation.

  • 5
    Solid Piece of Kit

    Posted by Ed on 23rd May 2019

    This tool serves a single purpose and it works. Simple as that. Zero complaints and it gets the job done. Unless you just have to have a name brand, there's no need to spend the extra money. Buy with confidence.

  • 5
    Review of the Tube Block

    Posted by Mark M on 16th Sep 2018

    Solid tool, not sure what else you would need from it. Maybe two more screws on the other side? Worth the price!

  • 5
    Buffer tube block

    Posted by Kasey Nielson on 11th May 2018

    This thing is awesome! It holds the buffer tube rock steady while torquing the castle nut. Definitely worth every penny.

  • 4
    It works!

    Posted by seswho on 24th Apr 2018

    Got this device and used it right away to exchange the end plat on my AR15 build. It held the buffer tube perfectly so I could tighten down the castle nut.

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